Microfluidics-based sensing devices, specifically, have been used for various chemical and biological assays, cellular manipulations, and electronic skin applications due to its exceptional sensitivity, flexibility, and adaptability. By utilizing only a minute quantity of conductive liquid (e.g., metallic or ionic liquid), responses to an external load may be detected in a microfluidic-based device through alterations in the geometry or physical properties of the working liquid, such as variations in its capacitance. With the intrinsic mechanical deformability of liquids, the liquid-state device technology offers a suitable avenue for the advancement of conformal devices capable of undergoing an extreme degree of deformation without the conventional solid-state materials-associated plastic deformation, fracture, and delamination. In considering the liquid materials to be used in the microfluidics-based sensors, working fluid with low viscosity and high physicochemical stability is highly advantageous.
Commonly used microfluidics-based sensing devices are based on detection by measuring capacitance. It is generally more complicated to measure the force of the external loads.
Further, with its far-reaching technological impacts, pressure sensing is one of the most critical components for a wide range of emerging applications such as in soft robotics, wearable consumer electronics, smart medical prosthetic devices and electronics skins, and real-time healthcare monitoring. As the demands for these applications continue to soar, the demands for pressure sensing are likewise becoming more stringent, particularly that of lightweight, flexible, and low cost.
There is therefore a need for an improved pressure sensor which is able to achieve reliable measurements in a simple and cost effective manner, while being suitable for use in at least the applications stated above.